In many manufacturing operations, metal articles are cut or machined in a manner which leaves a burr. Removal of these burrs, referred to as deburring, has become an important step in the overall manufacturing process. A manufactured article will not be considered good quality, and in most cases not even of acceptable quality, unless it is free of burrs. This is particularly true as quality standards increase. Thus, for many machined articles it is essential to achieve uniform and accurate deburring.
For some parts, deburring may be performed manually at a grinding station, using a grinding wheel. However, this method is not suitable for parts which are machined in such a way that there is no easy access to the burr. For instance, a tube which has one or more holes cut therein and oriented perpendicular to the tube axis will almost always have a burr along the inside edge, adjacent the holes.
To remove burrs of this type, it is necessary to extend some type of cutting tool into the end of the tube, with the distance of extension depending upon the distance of the hole from the end of the tube. The greater this distance, the more difficult the deburring operation. Also, if the tube has a relatively small inner diameter, this deburring operation becomes even more difficult.
While it is known to utilize machines of various type to perform operations such as cutting, champferring, grinding, machining, etc. at the ends of tubes, generally machines of this type are relatively complex, expensive and particularly suited to only one type of machining operation. Thus, such machines are not readily suited for the seemingly simple operation of removing burrs located inside of a tube, especially when such burrs must be removed from tubes of varying sizes and shapes, and with differently shaped holes.
Applicant developed a deburring piece which, in conjunction with a standard drill press, has proved suitable for deburring the inner edge of a hole accessible only via the inside surface of a tube. This deburring piece mounts to the vertical chuck of the drill press and has a midsection which extends horizontally in cantilever fashion from the axis of the drill. A vertically oriented countersink located at the outer end of the midsection is rotatably driven about a vertical axis via operation of the drill press. The rotation of the drill is coupled to the countersink via gears housed in the midsection. By manually extending a tube around the midsection in the proper orientation, with the tube oriented horizontal, the rotating countersink may be used to remove any burrs located along the inside surface of the tube, particularly burrs surrounding the inner edges of holes.
This manner of deburring tubes requires the use of the drill press, thus occupying a relatively cumbersome and awkward piece of machinery with an operation for which it has not been specifically designed. Also, to change over from deburring to drilling operations, and vice versa, additional manufacturing time is lost. As a result, when using a drill press for deburring, the seemingly simple operation of deburring has a disproportionately high cost.
With respect to the actual deburring step, because of the cantilevered orientation of the midsection with respect to the vertical drill, the midsection may sag downwardly to some degree at its outer end, particularly if the midsection is relatively long and extends a substantial distance into the tube. This sag adversely affects the gear drive, which may result in inconsistent or poor quality burr removal from the inside of the tube. Thus, to some degree, the distance of the hole to be deburred from the end of the tube dictates the overall consistency of burr removal.
Finally, in the past, internal deburring has generally not been regarded as a manufacturing operation which merits separate machinery, or a separate dedicated work station. Rather, deburring has been regarded as an ancillary operation.